Once again, I actually gave dozin that content about the ColorSound wah, and I don't know for certain (I haven't found an image where you could clearly read the model off the front of the pedal) but I think was a Wah+Vol rather than a straight Wah, because from time to time during the early 70's, you hear Jerry doing spacy segments featuring radical volume swells of a sort that would seem extremely difficult to pull off with the guitar's knob. An example of this is Garcia's noodling during the soundcheck portion of The Grateful Dead Movie.
As far as the "Vox in the 60's" info on dozin's page, I don't know where it originated. On Wikipedia this would have a little "[citation needed]" note next to it. Chris? Can you shed any light?
"There, in huge black letters, was 'The Grateful Dead'. It just... cancelled my mind out."-Garcia